As a light detection device, there is known a light detection device including a back-illuminated light receiving element which includes a plurality of light receiving portions, a circuit element, a bump which is disposed between the light receiving element and the circuit element, and an underfill which is disposed between the light receiving element and the circuit element. In such a light detection device, there is a case in which the underfill reaches a side surface of the light receiving element in order to reliably bond the light receiving element and the circuit element to each other.
However, when the underfill reaches the side surface of the light receiving element, there is a case in which light incident and refracted by the underfill is incident from the side surface of the light receiving element to the light receiving portion since the light receiving element is of a back illumination type. Since such light is noise light, the detection accuracy of the light detection device is degraded when such light is incident to the light receiving portion.
In order to solve the above-described problems, there is proposed a light detection device in which a resin containing a filler having a light shielding property is used as an underfill (for example, see Japanese Unexamined Patent Publication No. 2009-111090).